COMPARING THE ACCURACY OF GPS-ENABLED DEVICES FOR FIELD PURPOSES

In today's always connected world, GPS plays an important role in a variety of fields. From geology and geography to biology, GPS is playing a larger role in daily life, both personally and professionally. With emerging technology, devices such as tablets and GPS-enabled smartphones are becoming more competitive with GPS devices. We tested 14 GPS-enabled devices in 32 specific locations to see how much each device varied from surveyed base points. We used an aerial georeferenced map from the United States Geological Survey to plot a series of 15 base points within Land Between the Lakes National Recreation area. These base points have no cellular reception so tested devices could not triangulate locations from cell towers. We then located 17 sites using the same methods in downtown Nashville, TN in locations that would stress the accuracy of tested devices, such as near large buildings and metal bridges.

With all the GPS-enabled devices, we tested the accuracy of each device by measuring five times, then calculating an average. We then compared the data against surveyed base points. Coordinate data was plotted onto an aerial image map using ArcMap 10.0 and distance variance was calculated for each test device. A Dixion Q-test was conducted to exclude outliers in the data. To calculate spatial accuracy and precision a Root Mean Square Error test and Confidence Interval test was conducted. GPS-enabled devices accuracy is variable according to type of device and conditions which they are used.